Molecular hydrogen mass as a function of stellar mass for galaxies in our simulation. In addition to contours, solid circles display the median $\mathrm{MH}2$ within bins of stellar mass, along with the 25%–75% percentiles for model galaxies with MH2 > 0. To facilitate comparison, the dotted line in the central and right panels corresponds to the z = 0 relation. The colour contours delineate grids containing a specific number of galaxies as indicated in the colour bar, utilizing 0.2 dex-wide bins along both the x and y axes. Empty circles in the left panel represent the xCOLD GASS sample reported in Saintonge et al. (2017); non-detection in this sample is represented by downward arrows (0.01 < redshift < 0.05).